NEVER energy conserving (messes up your clutch). (most 5Ws)
Use a thicker oil unless racing in summer -- better protection, 20W or 15W.
In cold weather, use a non-energy conserving 10W or 15W (or even 5W or 0W if you're tracking it seriously). The thicker the oil, the better the protection (GENERALLY). But the thinner it is, the more HP (GENERALLY). Mind you, we're talking 1-2 HP or so, not enough to notice for street riding. Cold weather, the thinner oil will be better for startup protection (IE full synth).
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